With single spur gears, a pair of gears forms a gear stage. In the event that you connect several equipment pairs one after another, this is known as a multi-stage gearbox. For every gear stage, the direction of rotation between the drive shaft and the result shaft is usually reversed. The entire multiplication element of multi-stage gearboxes can be calculated by multiplying the ratio of every gear stage.
The drive speed is reduced or increased by the factor of the apparatus ratio, depending on whether it’s a ratio to slower or a ratio to fast. In nearly all applications ratio to gradual is required, since the drive torque is certainly multiplied by the overall multiplication factor, unlike the drive velocity.
A multi-stage spur gear can be realized in a technically meaningful method up to gear ratio of approximately 10:1. The reason for this lies in the ratio of the amount of tooth. From a ratio of 10:1 the driving gearwheel is extremely small. This has a poor effect on the tooth geometry and the torque that is becoming transmitted. With planetary gears a multi-stage gearbox is extremely easy to realize.
A two-stage gearbox or a three-stage gearbox can be achieved by merely increasing the distance of the ring equipment and with serial arrangement of several individual planet levels. A planetary equipment with a ratio of 20:1 could be manufactured from the individual ratios of 5:1 and 4:1, for instance. Rather than the drive shaft the planetary carrier provides the sun equipment, which drives the next world stage. A three-stage gearbox is usually obtained through increasing the space of the ring gear and adding another planet stage. A transmitting ratio of 100:1 is obtained using individual ratios of 5:1, 5:1 and 4:1. Basically, all individual ratios could be combined, which results in a big number of ratio options for multi-stage planetary gearboxes. The transmittable torque can be increased using extra planetary gears when performing this. The direction of rotation of the drive shaft and the output shaft is generally the same, so long as the ring equipment or casing is fixed.
As the amount of equipment stages increases, the efficiency of the overall gearbox is reduced. With a ratio of 100:1 the performance is leaner than with a ratio of 20:1. In order to counteract this situation, the actual fact that the power loss of the drive stage is definitely low should be taken into thought when working with multi-stage gearboxes. That is achieved by reducing gearbox seal friction reduction or having a drive stage that’s geometrically smaller, for instance. This also decreases the mass inertia, which is certainly advantageous in dynamic applications. Single-stage planetary gearboxes will be the most efficient.
Multi-stage gearboxes can also be realized by combining different types of teeth. With the right position gearbox a bevel gear and a planetary gearbox are simply combined. Here too the overall multiplication factor is the product of the individual ratios. Depending on the type of gearing and the kind of bevel gear stage, the drive and the result can rotate in the same path.
Benefits of multi-stage gearboxes:
Wide range of ratios
Continuous concentricity with planetary gears
Compact design with high transmission ratios
Combination of different gearbox types possible
Wide variety of uses
Disadvantages of multi-stage gearboxes (in comparison to single-stage gearboxes):
More complex design
Lower amount of efficiency
The automatic transmission system is very crucial for the high-speed vehicles, where the planetary or epicyclic gearbox is a typical feature. With the increase in design intricacies of planetary gearbox, mathematical modelling has become complex in character and therefore there is a need for modelling of multistage planetary gearbox including the shifting scheme. A random search-centered synthesis of three examples of freedom (DOF) high-swiftness planetary gearbox provides been offered in this paper, which derives a competent gear shifting mechanism through designing the transmission schematic of eight speed gearboxes compounded with four planetary equipment sets. Furthermore, with the help of lever analogy, the transmission power flow and relative power effectiveness have been identified to analyse the gearbox style. A simulation-based screening and validation have already been performed which display the proposed model is definitely effective and produces satisfactory shift quality through better torque characteristics while shifting the gears. A fresh heuristic solution to determine ideal compounding arrangement, based on mechanism enumeration, for designing a gearbox design is proposed here.
Multi-stage planetary gears are trusted in many applications such as automobiles, helicopters and tunneling uninteresting machine (TBM) because of their advantages of high power density and huge reduction in a small quantity [1]. The vibration and noise complications of multi-stage planetary gears are often the focus of interest by both academics and engineers [2].
The vibration of simple, single-stage planetary gears has been studied by many researchers. In the early literatures [3-5], the vibration structure of some example planetary gears are recognized using lumped-parameter models, however they didn’t give general conclusions. Lin and Parker [6-7] formally identified and proved the vibration framework of planetary gears with the same/unequal world spacing. They analytically classified all planetary gears settings into exactly three categories, rotational, translational, and planet settings. Parker [8] also investigated the clustering phenomenon of the three mode types. In the recent literatures, the systematic classification of settings were carried into systems modeled with an elastic continuum band equipment [9], helical planetary gears [10], herringbone planetary gears [11], and high swiftness gears with gyroscopic effects [12].
The organic frequencies and vibration modes of multi-stage planetary gears have also received attention. Kahraman [13] set up a family group of torsional dynamics models for substance planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic style of substance planetary gears of general description including translational examples of freedom, which enables an infinite number of kinematic combinations. They mathematically proved that the modal features of substance planetary gears had been analogous to a straightforward, single-stage planetary gear program. Meanwhile, there are various researchers concentrating on the nonlinear dynamic features of the multi-stage planetary gears for engineering applications, such as for example TBM [15] and wind turbine [16].
According to the aforementioned versions and vibration framework of planetary gears, many experts concerned the sensitivity of the organic frequencies and vibration modes to system parameters. They investigated the effect of modal parameters such as for example tooth mesh stiffness, world bearing stiffness and support stiffness on planetary gear natural frequencies and vibration modes [17-19]. Parker et al. [20-21] mathematically analyzed the consequences of style parameters on organic frequencies and vibration settings both for the single-stage and substance planetary gears. They proposed closed-form expressions for the eigensensitivities to model parameter variants based on the well-defined vibration mode properties, and founded the relation of eigensensitivities and modal energies. Lin and Parker [22] investigated the veering of planetary equipment eigenvalues. They utilized the organized vibration modes showing that eigenvalue loci of different setting types always cross and the ones of the same mode type veer as a model parameter is varied.
However, many of the existing studies just referenced the technique used for single-stage planetary gears to investigate the modal features of multi-stage planetary gears, while the differences between both of these types of planetary gears had been ignored. Because of the multiple examples of freedom in multi-stage planetary gears, more descriptive division of natural frequencies are multi stage planetary gearbox required to analyze the impact of different system parameters. The aim of this paper is usually to propose an innovative way of examining the coupled settings in multi-stage planetary gears to investigate the parameter sensitivities. Purely rotational amount of freedom models are accustomed to simplify the analytical investigation of equipment vibration while keeping the main dynamic behavior produced by tooth mesh forces. In this paper, sensitivity of natural frequencies and vibration modes to both gear parameters and coupling shaft parameters of multi-stage planetary gears are studied.
1. Planetary gear sets are available in wide reduction gear ratios
2. Gear established can combine the same or different ratios
3. Planetary gear set comes in plastic, sintered metal, and steel, depending on different application
4. Hight efficiency: 98% efficiency at single reduction, 95% at double reduction
5. Planetary gear established torque range: Low torque, middle torque, high torque
6. Easy linking with couplings, input shafts, output shafts
The planetary gear is a special kind of gear drive, in which the multiple planet gears revolve around a centrally arranged sunlight gear. The planet gears are mounted on a world carrier and engage positively within an internally toothed band gear. Torque and power are distributed among many planet gears. Sun equipment, planet carrier and band gear may either be generating, driven or set. Planetary gears are found in automotive structure and shipbuilding, aswell as for stationary make use of in turbines and general mechanical engineering.
The GL 212 unit allows the investigation of the dynamic behaviour of a two-stage planetary gear. The trainer contains two planet gear units, each with three planet gears. The ring gear of the initial stage is usually coupled to the planet carrier of the next stage. By fixing individual gears, it is possible to configure a total of four different transmission ratios. The apparatus is accelerated with a cable drum and a variable set of weights. The group of weights is elevated with a crank. A ratchet stops the weight from accidentally escaping. A clamping roller freewheel allows free further rotation following the weight has been released. The weight is captured by a shock absorber. A transparent protective cover stops accidental contact with the rotating parts.
To be able to determine the effective torques, the power measurement measures the deflection of bending beams. Inductive speed sensors on all drive gears allow the speeds to become measured. The measured ideals are transmitted right to a Computer via USB. The data acquisition software is roofed. The angular acceleration could be read from the diagrams. Effective mass occasions of inertia are dependant on the angular acceleration.
investigation of the powerful behaviour of a 2-stage planetary gear
three planet gears per stage
four different transmission ratios possible
equipment is accelerated via cable drum and variable set of weights
weight raised by hand crank; ratchet prevents accidental release
clamping roller freewheel allows free further rotation following the weight has been released
shock absorber for weight
transparent protective cover
push measurement on different gear stages via 3 bending bars, display via dial gauges
inductive speed sensors
GUNT software for data acquisition via USB under Windows 7, 8.1, 10
Technical data
2-stage planetary gear
module: 2mm
sun gears: 24-tooth, d-pitch circle: 48mm
world gears: 24-tooth, d-pitch circle: 48mm
ring gears: 72-tooth, d-pitch circle: 144mm
Drive
group of weights: 5…50kg
max. potential energy: 245,3Nm
Load at standstill
weight forces: 5…70N
Measuring ranges
speed: 0…2000min-1
230V, 50Hz, 1 phase
230V, 60Hz, 1 stage; 120V, 60Hz, 1 phase
UL/CSA optional
he most basic kind of planetary gearing involves three sets of gears with different degrees of freedom. Planet gears rotate around axes that revolve around a sun gear, which spins in place. A ring equipment binds the planets externally and is completely set. The concentricity of the planet grouping with the sun and ring gears means that the torque bears through a straight line. Many power trains are “comfortable” lined up straight, and the absence of offset shafts not merely decreases space, it eliminates the need to redirect the power or relocate other elements.
In a simple planetary setup, input power turns sunlight gear at high swiftness. The planets, spaced around the central axis of rotation, mesh with the sun and also the fixed ring gear, so they are forced to orbit as they roll. All of the planets are mounted to a single rotating member, called a cage, arm, or carrier. As the earth carrier turns, it delivers low-speed, high-torque output.
A set component isn’t constantly essential, though. In differential systems every member rotates. Planetary arrangements such as this accommodate a single result powered by two inputs, or an individual input driving two outputs. For example, the differential that drives the axle within an car can be planetary bevel gearing – the wheel speeds represent two outputs, which must differ to handle corners. Bevel gear planetary systems operate along the same basic principle as parallel-shaft systems.
A good simple planetary gear train offers two inputs; an anchored band gear represents a continuous input of zero angular velocity.
Designers can move deeper with this “planetary” theme. Compound (as opposed to basic) planetary trains possess at least two world gears attached in range to the same shaft, rotating and orbiting at the same speed while meshing with different gears. Compounded planets can have different tooth figures, as can the gears they mesh with. Having this kind of options greatly expands the mechanical possibilities, and allows more decrease per stage. Substance planetary trains can simply be configured so the world carrier shaft drives at high velocity, while the reduction issues from sunlight shaft, if the designer prefers this. Another thing about substance planetary systems: the planets can mesh with (and revolve around) both fixed and rotating exterior gears simultaneously, therefore a ring gear isn’t essential.
Planet gears, for his or her size, engage a whole lot of teeth as they circle the sun gear – therefore they can certainly accommodate many turns of the driver for each result shaft revolution. To execute a comparable decrease between a standard pinion and gear, a sizable gear will have to mesh with a rather small pinion.
Basic planetary gears generally provide reductions as high as 10:1. Substance planetary systems, which are more elaborate compared to the simple versions, can offer reductions often higher. There are apparent ways to additional reduce (or as the case may be, increase) swiftness, such as for example connecting planetary levels in series. The rotational output of the 1st stage is linked to the input of the next, and the multiple of the individual ratios represents the ultimate reduction.
Another choice is to introduce standard gear reducers into a planetary train. For example, the high-acceleration power might go through a typical fixedaxis pinion-and-gear set prior to the planetary reducer. Such a configuration, known as a hybrid, may also be preferred as a simplistic option to additional planetary phases, or to lower insight speeds that are too much for a few planetary units to take care of. It also provides an offset between your input and output. If a right angle is necessary, bevel or hypoid gears are occasionally mounted on an inline planetary program. Worm and planetary combinations are uncommon since the worm reducer by itself delivers such high adjustments in speed.